During her intake interview, a 44-year-old client endorses that in the past, she has had problems receiving care because all her past providers, both male and female, have fallen in love with her and want to pursue her sexually. She denies hallucinations or other symptoms. She is well groomed and articulate. Select the most appropriate diagnosis?

Choice A reason: Schizoaffective disorder requires the presence of a major mood episode (mania or depression) along with core symptoms of schizophrenia. The client in this scenario does not report any mood disturbances, nor does she meet the criteria for schizophrenia, making this diagnosis inappropriate based on the available clinical data. Choice B reason: Schizophrenia involves a range of cognitive, behavioral, and emotional dysfunctions, including disorganized speech, hallucinations, and negative symptoms. This client is described as well-groomed and articulate, and she explicitly denies hallucinations. Her functioning outside of the specific belief about her providers appears intact, which argues against a schizophrenia diagnosis. Choice C reason: Brief psychotic disorder is characterized by the sudden onset of psychotic symptoms that last at least 1 day but less than 1 month, with an eventual return to full premorbid functioning. The client’s belief about her providers appears to be a long-standing pattern ("all her past providers"), which suggests a more chronic delusional process. Choice D reason: Delusional disorder is the most appropriate diagnosis. It is characterized by the presence of one or more delusions (in this case, erotomanic or persecutory in nature regarding her providers) for a duration of 1 month or longer. In this disorder, apart from the impact of the delusions, psychosocial functioning is not markedly impaired, and behavior is not obviously bizarre or odd.